source: vendor/automake/1.4-p6/acinstall

#! /bin/sh

# Install an aclocal-style M4 file.  A script is needed to do this
# because we want to do serial-number checking; newer versions of
# macro files should always be preferred.

# Usage:
#  acinstall file directory installprogram [install-args]...

file="$1"
dir="$2"
shift
shift

localserial=`grep '^# serial ' $file | sed -e 's/^# serial \([0-9][0-9]*\).*$/\1/; q'`
if test -z "$localserial"; then
   echo "acinstall: no serial number in $file" 1>&2
   exit 1
fi

# Maybe if the installed file has no serial number we should just
# assume it is ancient.
instserial=`grep '^# serial ' $dir/$file | sed -e 's/^# serial \([0-9][0-9]*\).*$/\1/; q'`
if test -z "$instserial"; then
   echo "acinstall: no serial number in $dir/$file" 1>&2
   exit 1
fi

if test $localserial -lt $instserial; then
   # Installed file is newer.
   exit 0
fi

# Install the file.
$* $file $dir/$file